JP3010614B2 - Mounting structure of flat semiconductor rectifier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat semiconductor rectifier used in a rectifier, which breaks down in use and generates an arc inside the rectifier. The present invention relates to a mounting structure of a flat semiconductor rectifying element which does not spill to the outside and damage a nearby structure.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view showing a conventional flat semiconductor rectifier and its mounting structure. In this figure, a flat semiconductor rectifying element 1 is mounted so as to be sandwiched between a cooling conductor 2 and a connection bar 3. The flat semiconductor rectifier 1 includes a semiconductor substrate 13, internal components 14 in close contact with one surface of the semiconductor substrate 13,
Electrodes 11 and 12 sandwiching these from both sides, these electrodes 1
Metal flanges 16 and 17 extending to the outer diameter side from 1 and 12 respectively, and a ceramic envelope 15 attached to the outer diameter end of these flanges 16 and 17 are provided. Semiconductor substrate 13 which is the main body of flat semiconductor rectifier 1
Is located in a closed space surrounded by the electrodes 11, 12, the flanges 16, 17 and the envelope 15. When the flat semiconductor rectifier 1 is off, the electrodes 11
Since a high voltage is applied between and, the envelope 15 is provided with a flange similar to an insulator in order to withstand this high voltage. Although only one collar is shown in this drawing, a plurality of collars may be provided. The flange 16 has a structure in which a curved portion 18 is provided between the electrode 11 and the envelope 15 to absorb a manufacturing dimensional error of each, and the same applies to the flange 17.

[0003] In the flat semiconductor rectifying element 1, dielectric breakdown may occur in the semiconductor base 13 for some reason during the OFF period, and an arc may be generated inside the semiconductor base 13. Of course, the occurrence probability of such a phenomenon is very small, but the number of flat semiconductor rectifiers 1 used in one rectifier is very large and used for a long period of time. Such a dielectric breakdown phenomenon cannot be ignored, and once such a phenomenon occurs, considerations are given to prevent it from spreading to other parts and causing an accident.

When the semiconductor substrate 13 breaks down, the electrodes 11
An arc is generated between the inner space 19 and the surrounding space, and in particular, a high-temperature gas including a metal gas due to evaporation of the metal including the electrodes 11 and 12 serving as spot points is rapidly generated, and the internal space 19 is formed. Increase internal pressure. When such a breakdown of the flat semiconductor rectifier element 1 occurs, measures such as separating the corresponding flat semiconductor rectifier element 1 from a circuit are taken. There is a possibility that the failure may develop before the high-temperature gas is ejected to the outside and damages nearby structures such as the connection bar 3 and the cooling conductor 2.

The flat semiconductor rectifier element 1 itself can be easily recovered by replacing the one that has undergone insulation breakdown, but in many cases, it cannot be easily replaced when the other structures are damaged. Therefore, it is necessary to prevent the breakdown of the flat semiconductor rectifier element 1 from spreading to other structures as much as possible. The above-mentioned internal pressure rise causes mechanical destruction at the curved portion 18 of the flange 16 and the curved portion without the reference numeral of the flange 17, and a crack is generated in this portion, and the above-described high-temperature gas is ejected from the gap. As a result, the connection bar 3 or the cooling conductor 2 is damaged.

[0006]

As described above, there is a problem that an external structure may be damaged due to dielectric breakdown of the semiconductor substrate 12. SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem and provide a flat semiconductor rectifying element which can reinforce a curved portion of a flange, which is the weakest point in terms of mechanical strength, to prevent hot gas from being ejected to the outside. It is to provide a mounting structure.

[0007]

According to the present invention, there is provided a disk-shaped semiconductor substrate, two substantially disk-shaped electrodes sandwiching the semiconductor substrate from both sides, and an outer periphery of an insulator. One electrode of the flat semiconductor rectifying device comprising a container and two ring-shaped flanges connecting the envelope and the two electrodes is attached to the first conductor, and the other electrode is attached to the second conductor. In the mounting structure of the flat semiconductor rectifying element mounted on the semiconductor device, a ring is provided in a gap between the first conductor and the flange facing the same and a gap between the second conductor and the flange facing the same. The filling shall be made by inserting a ring-shaped metal plate and an elastic body plate in an integrated manner, and the insulating elastic body shall be covered by covering the envelope. And the stuffing is ring-shaped A metal plate and an elastic body plate are stacked and integrated, and an insulating elastic body is provided to cover the envelope, and the elastic body covering the envelope is provided on the first conductor side. And a second conductor side, and each elastic body is formed and attached integrally with the above-mentioned ring-shaped elastic body plate, and the elastic body covering the envelope is applied. It is assumed that the liquid resin is cured.

[0008]

In the structure of the present invention, a ring-shaped filling is inserted into a gap between the first conductor and the flange facing the same and a gap between the second conductor and the flange facing the same. When the internal arc is generated and the internal pressure of the flat semiconductor rectifier rises, the padding covers the curved portion of the flange, which is the mechanical weakest point, so that the mechanical strength of this part is reinforced and the hot gas flows from this part. No eruption. In addition, by forming the above-described padding by integrally forming a ring-shaped metal plate and an elastic body plate, it is possible to absorb a manufacturing error of a gap size by compressing the elastic body plate. In addition, by providing an insulating elastic body over the envelope, the flange is reinforced and it becomes difficult for high-temperature gas to be blown out, so that the internal pressure further rises and the envelope is cracked and scattered. Even in some cases, scattering is prevented or reduced by the elastic body. Further, the elastic body that covers the envelope is separated into a first conductor side and a second conductor side, and each elastic body is integrally formed and attached with each of the above-described padded elastic body plates. By adopting the structure, the elastic body covering the envelope can be securely held and fixed. Alternatively, the elastic body covering the envelope may be formed by applying a liquid resin and curing the liquid resin.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.
FIG. 1 is a sectional view showing an embodiment of the present invention, and the same members as those in FIG. In this figure, the flanges 16 and 1 which are the mechanical weakest points against the internal pressure rise when an arc is generated inside are shown.
7 to reinforce the mechanical strength of the curved portion 18
The point provided with 40 is a difference from the conventional mounting structure of FIG. The padding 4 includes a metal plate 41 which is a ring-shaped disk made of metal such as stainless steel and an elastic plate 42 such as silicon rubber.
Are bonded together, and are packed in the gap between the cooling conductor 2 and the flange 16. The elastic plates 42 are bonded together in order to absorb manufacturing errors in the dimensions of the gap and to hold down the flange 16 with a required force. When the flange 16 is actually broken due to an increase in internal pressure, the metal plate 41 mainly serves to shut off high-temperature gas spouted. Even if it is ejected, it is interrupted by the padding 4 and the direction of the ejection is the right and left direction in the drawing, which is a radial direction, and it does not directly blow onto the cooling conductor 2 or the connection bar 3, so that these are hardly damaged.

As an example of actual dimensions of the padding 4, the gap between the cooling conductor 2 and the flange 16 is about 2 mm, whereas the thickness of the metal plate 41 and the thickness of the elastic plate 42 are 1 mm. About 0.5 mm is adopted. The structure of the padding 40 packed in the gap between the flange 17 and the connection bar 3 is the same as that of the padding 4 described above, and the description is omitted. In principle, it is possible to omit the elastic plate 42 and to use only the metal plate 41 for the configuration of the paddings 4 and 40. In this case, however, in order to cope with a variation in the size of the gap, the filling of the metal plate 41 is performed. It is necessary to adjust the thickness by adjusting the actual product. However, in a large-capacity rectifier using the flat semiconductor rectifying element 1, a large number of elements are used, and it takes an enormous amount of time to adjust the thickness dimension of the metal plate 41 for each of these elements. That is not practical. If the number of elements used is small, it is also practical to omit the elastic body plate 42 to simplify it.

The method of inserting the fillings 4 and 40 is as follows. First, the padding 40 is placed in a predetermined position on the connection bar 3 in advance, and the flat semiconductor rectifier 1 is attached to the connection bar 3. Next, the cooling conductor 2 is attached after the padding 4 is attached thereto. Since the flat semiconductor rectifying element 1 and the cooling conductor 2 are tightened by bolts (not shown), the elastic body plate 42 contracts due to the tightening force at this time to absorb a dimensional error. Conversely to this procedure, a method of assembling other components before attaching to the connection bar 3 and finally attaching to the connection bar 3 may be adopted. In any case, the method for inserting the fillings 4 and 40 is not limited to the method described above.

FIG. 2 is a sectional view showing another embodiment of the present invention. The same members as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted. The difference between FIG. 1 and FIG. 1 is that in FIG. 1, the elastic plate 42 of the padding 4 is a ring-shaped plate having the same width as the metal plate 41, whereas the elastic plate 43 of the padding 4A of FIG.
Is a point covering the outer diameter surface of the envelope 15. From this point, the name of the padding may not be appropriate, so the same name as in FIG. 1 is used here.

In the case of FIG. 1, the curved portions 18 of the flanges 16 and 17, which are the mechanical weakest points, are strengthened by the paddings 4 and 40, and as a result, a crack is generated in the envelope 15 due to an increase in the internal pressure, and the surroundings 15 are scattered. There is a danger of hitting an object and damaging it. By adopting a configuration in which the envelope 15 is covered with the elastic plate 43 as shown in FIG.
3 or is not scattered or reduced to a lesser extent. Although high-temperature gas is ejected from the cracked portion, there is substantially no problem since the direction is such that the connecting bar 3 and the cooling conductor 2 are hardly damaged as in the case of FIG.

The method of inserting the paddings 4A and 40A is basically the same as that of FIG. Although the upper and lower elastic plates 43 collide with the tip of the brim of the envelope 15, it is not always necessary to integrate these portions by bonding or the like. This is because the elastic body plate 43 is ineffective and has no ability to prevent the ejection of the high-temperature gas with respect to a large increase in the internal pressure that causes a crack in the envelope 15.

As the elastic plate 43, a portion corresponding to the elastic plate 42 of FIG.
It is also possible to adopt a configuration in which the portion that covers 5 is separated. In particular, the portion covering the envelope 15 may be formed by applying a liquid resin to a predetermined thickness and curing the resin. However, in this case, since a long time is required for the coating operation, it is not always appropriate when the number of the elements 1 is large.

The cooling conductor 2 and the connecting bar 3 to which the flat semiconductor rectifying element 1 is attached vary depending on the number of series and parallel flat semiconductor rectifying elements 1 in one arm. As always, the cooling conductor 2 can be generally referred to as a first conductor and the connection bar 3 as a second conductor.

[0017]

As described above, according to the present invention, the internal pressure of the flat type semiconductor rectifier is increased by inserting the padding into the gap between the first conductor and the second conductor and the flanges facing each other. The padding covers the curved portion of the flange, which is the mechanical weakest point with respect to, so that the mechanical strength of this portion is reinforced and hot gas does not blow out from this portion, and the first conductor and the second conductor It is necessary to avoid the ripple effect that nearby structures such as conductors are damaged by high-temperature gas and not only broken flat semiconductor rectifiers but also these damaged structures must be replaced. The effect that it can be obtained is obtained.

Further, by forming the above-mentioned padding integrally with a ring-shaped metal plate and an elastic body plate, the elastic body plate can absorb the manufacturing error of the gap size. This eliminates the need to adjust the thickness of the padding, thereby preventing an increase in the number of processing steps of a rectifier using a flat semiconductor rectifier. Also,
By providing an insulating elastic body that covers the envelope, even if the internal pressure further increases due to the reinforcement of the flange and the envelope may be cracked and scattered, the elastic body scatters. Can be prevented or reduced, and the effect of avoiding damage to surrounding structures by the fragments of the scattered envelope can be obtained.

The elastic body covering the envelope is separated into a first conductor side and a second conductor side, and each elastic body is formed integrally with each of the above-described padded elastic body plates. By adopting the configuration in which the elastic body is covered by the mounting, the effect of holding and fixing the elastic body covering the envelope can be ensured, and the manufacturing cost and the assembly cost can be reduced.

The same effect as described above can also be obtained by forming the elastic body covering the envelope by applying a liquid resin and curing the liquid resin.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a flat semiconductor rectifier and a mounting structure thereof according to an embodiment of the present invention.

FIG. 2 is a sectional view of a flat semiconductor rectifier and a mounting structure thereof according to another embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a conventional flat semiconductor rectifier and its mounting structure.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 flat semiconductor rectifying element 11, 12 electrode 13 semiconductor base 15 envelope 16, 17 flange 18 curved portion 2 cooling conductor (first conductor) 3 connection bar (second conductor) 4, 40, 4A, 40A padding 41 Metal plate 42, 43 Elastic body plate

Claims (5)

(57) [Claims] 1. A disk-shaped semiconductor substrate, two substantially disk-shaped electrodes sandwiching the semiconductor substrate from both sides, an insulator envelope, and two insulators connecting the envelope to the two electrodes. In a flat semiconductor rectifying element mounting structure in which one electrode of a flat semiconductor rectifying element formed of a ring-shaped flange is mounted on a first conductor and the other electrode is mounted on a second conductor, A flat semiconductor rectifier, wherein ring-shaped fillings are inserted into a gap between a conductor and a flange facing the same and a gap between the second conductor and a flange facing the second conductor. Mounting structure. 2. The mounting structure of a flat semiconductor rectifier according to claim 1, wherein the padding is formed by laminating a ring-shaped metal plate and an elastic body plate. 3. The mounting structure for a flat semiconductor rectifier according to claim 1, wherein an insulating elastic body is provided so as to cover the envelope. 4. A padding comprising a ring-shaped metal plate and an elastic body plate which are laminated and integrated, and an insulating elastic body is provided so as to cover the envelope. An elastic body covering the first and second conductors is separated into a first conductor side and a second conductor side, and each of the elastic bodies is integrally formed and attached to each of the ring-shaped elastic body plates. A mounting structure for the flat semiconductor rectifier according to claim 1. 5. The mounting structure for a flat semiconductor rectifier according to claim 3, wherein the elastic body covering the envelope is formed by curing the applied liquid resin.